Petroleum-derived base oils are mixtures of liquid hydrocarbons having desired physical properties (e.g., pour point, cloud point, viscosity, density, flash point or stability against oxidation) selected based on the desired end use application (e.g., lubricating oils, greases, transformer oils, refrigeration oils or process oils). Base oils may be used as is, blended with another oil or feedstock, or combined with one or more additives. Base oils typically are classified as either naphthenic or paraffinic. In general, naphthenic base oils are less widely used than paraffinic base oils, but are preferred for some industrial applications. However, the production of quality naphthenic base oils requires careful selection of processing steps in order to meet target performance characteristics and production costs.